资料来源 : Webster's Revised Unabridged Dictionary (1913)

   {Permanent way}, the roadbed and superstructure of a finished
      railway; -- so called in distinction from the contractor's
      temporary way.

   {Permanent white} (Chem.), barium sulphate ({heavy spar}),
      used as a white pigment or paint, in distinction from
      white lead, which tarnishes and darkens from the formation
      of the sulphide.

   Syn: Lasting; durable; constant. See {Lasting}.